The accident occurred about 3:30pm between kilometre markers 418-419 on Highway 12 (Lom Sak-Chumphae) in the Nam Nao National Park, reports the Bangkok Post.
The driver of the chartered bus died in the crash and all 46 passengers were injured. Forty-five were admitted to Nam Nao Hospital and one to Khon San Hospital.
The passengers were all members of a women’s group from Wapi Pathum district, Maha Sarakham province, on a field trip to Khao Kho in Phetchabun. They were on the way back to Maha Sarakham.
Police were investigating the cause of the accident.